Declaration

Overview

Use particle property controllers to change the properties of individual particles in an SCNParticleSystem object over time, with Core Animation semantics. For example, by associating a keyframe animation with a particle system’s color property, you can create a flame effect with particles that change from blue to white to orange as they rise.

A particle property controller animates a property of individual particles rendered by the particle system. By comparison, implicitly or explicitly animating properties of a SCNParticleSystem object affects the system as a whole. Consider the keyframe animation of colors described above—if you apply this animation directly to a particle system instead of using a property controller, all particles rendered by the system change color together instead of each one changing color as it rises.

Core Animation animations in SceneKit typically animate a change to a property as a function of time. By default, property controllers animate a particle property this way. However, by changing the inputMode property you can also create animations that animate a particle property as a function of distance from a specified node or of the value of another particle property. For example, you can use this option to make particles change color as they speed up and slow down.

For more details about particle systems and particle properties, see SCNParticleSystem.